Bag closing and sealing machine for stepped end bags



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R. H. AYRES ETAL BAG CLOSING AND SEALING MACHINE FOR STEPPED END BAGS --a-- NJ 0 May 7, 1968 Filed Aug. 20, 1965 1968 R. H. AYRES ETAL 3,381,448

BAG CLOSING AND SEALING MACHINE FOR STEPPED END BAGS- Filed Aug. 20, 1965 5 Sheets-Sheet 2 l //7 V////A FIE.

I14 f, k\ \2\ K m 1 l 49a I L p I 50a 49 ||1 H I so 1 III I 1! 1 $5 52 l I I I l l I I L 47/ 52 55a L 48 FI E. 5' m5 INVENTORS Flt/I420 1/- 4mm: #02040 A. Jam/sou /25 By 108 M YM [03 I040 26 United States Patent 3,381,448 BAG CLOSING AND SEALING MACHINE FGR STEiPED END BAGS Richard H. Ayres, Minneapolis, and Harold K. .Iohnson,

Bloomington, Minn., assignors to Bemis Company,

Inc., a corporation of Missouri Filed Aug. 20, I965, Ser. No. 481,304 7 Claims. (Cl. 53-373) ABSTRACT (BE THE DISCLOSURE on the horizontally extending bag portion. A shoe is mounted on the nozzle to cooperate with the folder blade in folding said bag portion. Spring steel plates are resiliently urged to position the belt guide plates mounted thereon to retain the inner runs adjacent one another.

This invention relates to new and novel apparatus for folding and sealing the stepped end portion of a stepped end bag to form a sealed bag top closure. More particularly this invention relates to new and novel apparatus for activating the hot melt adhesive on the bag top portion of a stepped end bag, folding over the bag top portion having the activated adhesive, and compressing the resulting bag closure to form a tight seal.

Powdered and granular material in to 100 lb. lots are presently being pack-aged and sold in multi-wall bags called stepped end bags. This type of bag is also sold under the trademark Pinch Bottom bag, this trademark being owned by St. Regis Paper Company. Such bags on their open inner wall have a step on which there is preapplied a hot melt adhesive. The apparatus of this invention is provided for forming a sealed bag top closure on the aforementioned type bags.

One of the objects of this invention is to provide new and novel apparatus for partially foldin the stepped end portion of a bag and activating the hot melt adhesive on the stepped end. Another object of the invention is to provide new and novel apparatus utilizing hot air for activating the hot melt adhesive on the partially folded end portion of a stepped end bag. A further object of this invention is to provide new and novel apparatus for partially folding the stepped end portion of a bag as it is being conveyed, next activate the hot melt adhesive on said partially folded end portion, and thence completing the fold and compressing the completed fold to obtain a tightly sealed bag top closure.

Other and further objects are those inherent in the invention herein illustrated, described and claimed, and will become apparent as the description proceeds.

To the accomplishment of the aforegoing and related ends, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail, certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

The invention is illustrated in the drawings in which the same numerals refer to corresponding parts and in which:

FIGURE 1 is a plan view of the apparatus of this invention, portions of the top plate being broken away to more clearly illustrate structure therebeneath;

FIGURE 2 is a side View generally taken along the line and in the direction of the arrows 2-2 of FIGURE 1, portions of the conveyor belt and the conveyor belt guide structure being broken away;

FIGURE 3 is an enlarged, horizontal fragmentary cross-sectional view generally taken along the line and in the direction of arrows 33 of FIGURE 2 t-o'illustra'te part of the drive structure, portions of FIGURE 3 being broken away to more clearly illustrate structure at a lower elevation;

FIGURE 4 is a further enlarged, transverse cross sectional view, said view being generally taken along the line and in the direction of arrows 44 of FIGURE 1 to show the creasing rollers and the mounting thereof;

FIGURE 5 is an enlarged transverse cross sectional view generally taken along the line and in the direction of the arrows 5-5 of FIGURE 1 to show the structure for partially folding the stepped end portion of the bag and applying hot air to melt the adhesive on the ste'pped end por'tionyi FIGURE 6 is a still further enlarged, fragmentary cross sectional view of part of the structure illustrated in FIGURE 5 to more clearly show the hot air nozzle applying hot air to a stepped end portion of a bag that is held in a partially folded condition by the folder blade, said view being taken through the bag longitudinally between the folded gusset panels at one end and the gusset panels at the other end;

FIGURE 7 is a plan view of the folder blade, a central portion of the folder blade being broken away;

FIGURE 8 is a side elevational view generally taken along the line and in the direction of the arrows 8-8 of FIGURE 7 to further illustrate the construction of the folder blade;

FIGURE 9 is a transverse cross sectional view generally taken along the line and in the direction of the arrows 9-9 of FIGURE 8;

FIGURE 10 is a transverse, rear end view of the folder blade, said view being generally taken along the line and in the direction of the arrows lit-ll) of FIGURE 8;

FIGURE 11 is a fragmentary plan view of the upper end portion of a gusseted stepped end bag in flat folded condition to show the pattern of hot melt adhesive on the bag top portion of said bags;

FIGURE 12 is a fragmentary end view of the bag of FIGURE 11 other than the bag has been opened; and

FIGURE 13 is a fragmentary transverse cross sectional view showing the resilient mounting of one of the belt guides.

Referring now in particular to FIGURES 1, 2 and 4, the apparatus of this invention, generally designated 10, includes a frame having a horizontal, elongated top mounting plate 11 and a vertical, longitudinally elongated mounting plate 12 that has its upper edge dependingly secured to one longitudinal edge of the mounting plate 11. Plate 12 is bolted or otherwise appropriately secured to a stand (not shown) whereby plates 11 and 12 are located a substantial distance above the floor. The stand mounts plates ll and 12 in overhanging relationship to a conveyor assembly, generally designated 17, that extends the longitudinal length of the machine 10 to support the bottom of a filled bag 15 as it is conveyed through the apparatus of this invention.

Directly below the rearward end portion of plate 11, there is provided a horizontal compression roller mounting plate 18, plate 13 being somewhat T-shaped in plan view. A plurality of spacer members 19 are dependingly secured to plate 11 and dependingly mount compression roller mounting plate 18 in horizontal spaced relationship to plate 11. A spacer plate 21) has opposite ends respectively secured to plate 18 and the rear transverse edge of plate 11.

The apparatus of this invention also includes a conveyor assembly, generally designated 16, for supportingly holding the bag top side walls closely adjacent one another at a proper elevation relative to conveyor 17 while the bag top is moved through the apparatus 19. For purposes of facilitating the further description of the apparatus 10, the vertical plane of conveyance of the bag top of the bag through the apparatus It) by conveyor assembly 16 will be referred to as the central longitudinal axis L-L of the machine, a location in a horizontal direction at right angles to said plane as transversely outwardly (right or left), the end of the machine where the bag enters as the forward end, and the end where the bag exits from the machine as the rear or back end. Thus as the bag top moves through the apparatus ltl, it is considered as being moved in a rearwardly direction.

The conveyor assembly 16 includes a pair of mounts 22. that are attached to a rear portion of plate 1.8 in transverse spaced relationship, each mount respectively journalling a shaft 23, 24 for rotation about a vertical axis with each shaft extending above and below plate 18. A pulley sheave 25 is keyed to the lower end of each of the shafts 23, 24. The forward end portion of the plate 11 has a pair of longitudinally elongated transverse slots 26, a shaft 28 being extended through the right hand slot and journaled for rotation by a mount 27. A shaft 29 is likewise extended through the left hand slot and is journaled for rotation by a mount 27 Each of the mounts 27 mount the respective shaft 28, 29 on plate 12 for adjustable longitudinal movement, there being provided a bolt 3t) threaded into each mount and rotatably extended through a bar 31 that is dependingly attached to the plate 12. Each of the shafts 23, 29 has a pulley sheave 33 keyed thereto.

Rearwardly of shafts 28, 29, a mounting block 36 is bolted to the under side of plate 11. A vertical bar 37 has 1 its upper end attached to the block 36 and has an apertured lower end through which the smooth central portion of a bolt 38 is extended. Bolt 38 slidably extends through a central portion of a pulley mount 39 and has a nut 46 threaded thereon. A washer 42 is provided on bolt 38 to abut against bar 37, a coil spring 41 being provided on bolt 38 to have one end abut against the washer and the opposite end to abut against the adjacent vertical surface of mount 39 in order to resiliently retain mount 39 in abutting relationship with nut 40.

A shoulder screw 43 has its threaded end portion threaded into block 36 to depend therefrom. The smooth intermediate portion of the shoulder screw extends through an aperture in the forward end of mount 39 and has a head abutting against the lower surface of said mount in order to permit mount 39 pivoting about a vertical axis, but at the same time prevent the mount moving in a vertical direction. Thus, screw 43 prevents vertical movement of mount 39 relative to plate 11, while due to sufficient play provided by the aperture in bar 37 through which bolt 38 is extended, mount 39 can pivot a limited amount about the vertical axis of screw 43 toward plate 37.

A vertical stud shaft 45 has its upper end secured in block 39 rearwardly of bolt 38, the stud shaft extending adjacent to, but out of engagement with block 36. A left hand creasing roller drive pulley 47 is rotatably mounted on the lower end of shaft 45, while a right hand creasing roller drive pulley 48 is rotatably mounted on the lower end of a vertical shaft 51. The upper end of shaft 51 is secured in block 36. Each of the pulleys 47, 48 has an upwardly extending annular flange to which there is respectively keyed a left creasing roller 49 and a right creasing roller 50. As may be noted from FIGURE 4, roller 50 has an annular groove 590, while roller 49 has an upper annular creasing flange 49a that normally extends into groove 50a.

A belt 52 having a generally straight length inner run 52a is extended around the pulley sheave 33 on shaft 29 and thence has its inner run extend rearwardly in abutting engagement with pulley sheave 47 and thence rearwardly to the pulley sheave 25 on shaft 23. Belt 52 then extends around sheave 25 and has an outer run 521) that extends forwardly into abutting engagement with pulley 47 and thence back to the pulley sheave on shaft 29. A shaft 53 is dependingly secured to block 36 and rotatably mounts an idler pulley 57 in position to bear against the outer run of belt 52 intermediate pulley 47 and the left front pulley sheave 33 such that the outer run of the belt bears against a substantial angular portion of pulley 47 to drive pulley 47.

A second belt 55 having a generally straight length inner run 55a is extended around the right front pulley sheave on shaft 28 and has its inner run extending rearwardly to pass in abutting engagement with pulley 48. Belt 55 then extends rearwardly to pass around the pulley sheave 25 on shaft 24, thence forwardly to pass in abutting engagement with pulley 4S and next back to the pulley sheave on shaft 28. A second shaft 53 mounts an idler pulley 57 in position to bear against the outer run of belt 55 intermediate the right sheave 33 and pulley 48 such that the outer run of belt 55 bears against a substantial angular portion of pulley 48 to drive pulley 43. Shafts 53 are depcndingiy mounted by block 36.

In order to drive the belts such that the inner runs 52a, 55a move in the same direction at the same rate, a gear 59 is keyed to the upper end of shaft 23 in driven relationship to a gear 66 keyed to the upper end of shaft 24 (see FIGURE 3). Since gear 59 is driven by gear 60, gear 59 rotates about the axis of shaft 23 in a direction opposite the direction of rotation of gear 69 about the axis of shaft 24. In order to drive the gear 60, a gear 61 is keyed to the lower end of the motor shaft 62a, gear 61 being in driving relationship to gear 60. A motor 62 is mounted on the rearward portion of plate 11 and has its motor shaft 620 extended downwardly through an appro priate aperture in plate 11.

In order to hold the length of the belt inner run 55a that extends between pulley 45 and the pulley sheave on shaft 24 adjacent run 52a, there is provided an elongated belt guide 64 that has a portion 64a with a groove along one vertical edge into which inner run 55a extends (see FIGURE 5). A plurality of longitudinally spaced, vertically elongated mounting members 65 support the belt guide 64 from plate 11 and at the same time retain the guide at a substantially lower elevation than plates 11 and 18. A second belt guide 67 having a groove into which a length of inner run 52a extends is provided for resiliently retaining the portion of run 52a that is transversely adjacent the forward end portion of guide 64 closely adjacent the corresponding portion of run 55a. A second belt guide 71 of the same construction as guide 67 is provided longitudinally rearwardly of guide 67 and transversely opposite the rear portion of guide 64.

In order to mount guides 67, 71, a longitudinally elongated bar 68 is dependingly secured to plate 11 adjacent its right longitudinal edge. A plurality of longitudinally spaced, vertically extending bars 69 and a corresponding number of spring steel plates 70 are provided. Bolts 71 are extended through the upper end portions of bars 69 and plates 76; and threaded into bar 68 such that there is a bar 69 intermediate each plate 7:) and the adjacent portion of bar 68. The lower ends of plates 70 are bolted at 72 to the adjacent portions of guides 67, 71 respectively. As may be noted from FIGURE 13, the bars 69 are of a length that their lower end portions are located a slight distance above guide 67. A bolt 74 is extended through apertures in the lower end portions of each set of bars 69 and plates 70, and has a nut threaded thereon to abut against bar 69. A coil spring '75 is provided on bolt 74 to have one end abut against plate 76 and an opposite end to abut against a washer 76 on bolt '74, the washer abutting against the head end of the bolt. As a result of providing spring 75 and sufiicient play in the aperture of plate 70 through which bolt 74 is extended; the lower end portion of plate 70 is resiliently retained in engagemeat with bar 69, but at the same time can move a limited amount in the direction of the arrow 77 away from the lower end portion of bar 69. As a result, when the top portion of the bag is being conveyed by the inner run of belts 52a, 55a transversely between guides 64 and 67 or 71, the respective guides 67, 71 can move a limited amount in the direction of the arrow 77 against the action of spring 75.

A pair of longitudinally spaced bolts 81 have their upper end portions extended through appropriate apertures vertically above the belt inner runs and rearwardly of the creasing rollers, there being provided upper and lower adjustments nuts 82 on the bolts for retaining said bolts in a vertically adjusted position relative plate 11. The lower ends of bolts 81 mount a longitudinally elongated blade mount 83 which in turn dependingly mounts the folder blade, generally designated 85. The folder blade is integrally formed and has a vertical, longitudinally extending backing plate 86 that is located above inner run 55a.

Blade 85 also includes a longitudinally central, planar horizontal portion 87 having a right edge joined to a backing plate 86, and a front edge integrally joined to a front portion 38 which initiates the folding of a bag top being conveyed adjacent thereto by belts 52, 55'. As may be noted from FIGURE 8, the left edge of portion 88 is gently curved upwardly to extend longitudinally forwardly of planar portion 37 while the right edge extends horizontally forwardly and in part is joined to the planar portion 86b of the backing plate and in part extends forwardly thereof. In a transverse vertical plane, portion 88 at the forward edge curves upwardly and transversely to the left, the amount of curvature being progressively less the more closely adjacent planar portion 37 that the transverse cross section is taken.

The folder blade also has a horizontal flange 89 that extends transversely to the left of backing plate portion 86b, and is in part joined to the curved portion 36a of the backing plate and also to the adjacent edge of portion 88. In this connection, it is to be noted that in horizontal cross section, portion 86a in a rearward direction curves transversely inwardly toward the plane of portion as!) whereby portions 36a and flange 89 bend the leading edge of a bag to the left side of portion 86b in the event that the upper edge portion of the bag top is inclined slightly toward the right. Further, as may be in part noted from FIGURES 1 and 2, flange 89 in part closely overlays the top surface of creasing roll 59 while the forward edge of portion 86 is closely adjacent a vertical surface portion of said creasing roll.

The folder blade also includes a rear portion 90 that has a front edge integrally joined to central portion 87 and a longitudinal edge integrally joined to the upper edge of backing plate portion 86b. Portion 9G is smoothly curved such as shown in FIGURES 8 and to, in a longitudinal rearward direction from central portion 87, curve downwardly such that at the rearward end of the folder blade there is provided a U-shaped web portion and a leg portion extending generally parallel to the transverse adjacent portion of the backing plate and transversely spaced therefrom by a distance substantially the same as the thickness of the folded bag top closure formed by apparatus 10.

Referring in particular to FIGURES 1, 2, 5 and 6, the hot air assembly includes a heater mount 93 attached to mounting plate 12 and a transversely elongated tube 94- that extends through appropriate apertures in plate 12 and mount 93, and transversely outwardly on either side thereof. A heater clamp 95 is clamped on tube 94, bolt 96 being extended through clamp 95 and a spacer 97 intermediate clamp 95 and mount 93 to be threaded into mount 9.3. Adapter 93 is connected to one end of tube 94 and to line 99 to conduct hot air under pressure from a conventional hot air source 1% to the tube M. The opposite end of tube 94 extends transversely across the folder blade in a vertical spaced relationship thereto, and mounts a downwardly extending tubular member 102. The lower end of tubular member 1tl2 mounts a transverse tubular member 1% which in turn mounts the hotair nozzle member that includes a hot air nozzle 104. Members 1G2, 193 have a fluid passageway for conducting fluid from the aforementioned opposite end of tubular member 94 to the plenum chamber ill-ta of nozzle 104.

The nozzle 104 is rectangular in transverse cross section and is elongated in the direction of movement of the bag through apparatus 10. The nozzle is mounted to underly nearly the entire longitudinal length of the central portion 87 of the folder blade. Further, the nozzle has a vertical side wall ill lo and a planar top wall 104]) that has a plurality of discharge apertures 107 that open to the plenum chamber 194a to permit discharge of air under pressure upwardly toward the central portion 87 of the folder blade. In this connection, there are provided longitudinally spaced apertures 107 along substantially the entire length of the top wall Illdb.

The nozzle member also includes a longitudinally elongated shoe 1% attached to vertical sidewall 104e, shoe 1% having a vertical surface extending parallel to backing plate portion 86b from the front end thereof to a location underlying the rear portion 96 such as shown in FIGURE 2. Further, the shoe has a front end portion lllfia that is curved to diverge outwardly from portion soar to in conjunction therewith form a throat for directing the leading edge 135 of a bag into the space between the adjacent planar surfaces of the shoe and the backing plate. Further, the shoe has an incline surface itldb that is inclined upwardly from adjacent the juncture of nozzle walls lil lb, lilac toward the juncture of central portion 87 and backing plate portion 8615.

Just rearwardly of the folder blade there is provided a compression roller assembly that includes a right hand compression roll 112 and a left hand compression roll 112, said rolls being mounted in transverse spaced relationship to rotatably depend from plate 18. On each of the shafts Z3, 24 there is keyed a driven compression roll 113. A belt 114- is extended around the left hand compression roll 112 and the left roll 113 to have an inner run vertically above the inner run 52a. Likewise the right hand rolls 112, 113 mount a belt 115 to have its inner run vertically above belt inner run 55a. As maybe noted from FIGURE 2, the lower horizontal edges of belts 114, 115 are approximately the same elevation as the lower edge of the backing plate as and only a slightly distance vertically above the upper edges of belts 52., 55. Two transverse rows of idler compression rollers 119 are dependingly mounted on plate 18 in position to resiliently retain the adjacent surfaces of the inner runs of belts 114, M5 closely adjacent one another (each of the rollers 119 having at least an annular surface portion made of resilient material). As may be noted from FIGURE 2, belts 31 5, 115 vertically extend from about the same elevation as the lower edge of plate 86 to a substantially higher elevation than portion 87.

Before proceeding with the description of the operation of the apparatus of this invention, the upper end portion of the stepped end bag 15 will be briefly described with reference to FIGURES 11 and 12. bag 15 includes a first side wall 1 .25, a second side wall 126 and a pair of gussets each having gusset panel 127 and a gusset panel 128. Each gusset panel 128 has one edge joined to the contignous edge of the side wall 126 and an opposite edge joined to the contiguous edge of the gusset panel 127. Each gusset panel 127 has one edge joined to the contiguous edge of the side wall 125. Each set of gusset panels 127', 128 forms an end wall of the bag.

Assuming that the bag 115 has been filled with product and the upper end portion of the bag has been folded such that the outer surface of the upper end portion of each gusset panel 12-7 abuts against the adjacent portion of gusset panel 128 and extends vertically above the product, the peripheral horizontal edge of side wall 126 is located at a substantially lower elevation than the corresponding edge of side wall 125. Each of the panels 128 has a horizontal edge 128:: located at a higher elevation than the bag top edge of wall 126, but at a lower elevation than the corresponding bag top end of panel 127. Further, the bag top edge of panel 127 is at a lower elevation than the bag top edge of wall 125. The bag is initially formed with a plurality of hot melt adhesive strips, for example th-rce strips, 131, 132 and 133. As may be noted from FIGURE 11, the strip 131 extends across the inner surface of panels 123 and the portion of side wall 125 intermediate said panels in a folded condi tion, strip 131 being above the top edge of the side wall 126. A second strip of adhesive 132 is provided to extend across the outer surfaces of panels 127 that extends above panels 128 and the surface portion of side wall 125 that is intermediate panels 127 in a bag top folded condition. A third strip of adhesive 133 is provided across the top edge portion of side Wall 125 at an elevation above the L top edges of panels 127.

Using the apparatus of this invention, a stepped end bag is filled with product and the top portion of bag is folded so that the upper portions of the bag gussets and the side walls extend in a vertical condition upwardly above the product but with the side wall 126 closely adjacent side wall 125. With the thus filled bag on the conveyor 17, the bag is conveyed such that the leading edge 135 is moved into the entry nip of belts 52, 55 whereby the belts conveyingly engage the side walls 125, 126 at a substantial distance below the top edge of wall 126 but above the level of product in the bag. At this time inner run 55a abuts against the upper portion of side wall 125 while inner run 52a abuts against the upper portion side wall 126 whereby the inner runs of the belts 52, 55 supportingly hold side walls 125, 126 in abutting relationship to each other or to the adjacent gusset panel, and the upper portions of the respective set of panels 127, 128 in surface abutting relationship. The bag is thus conveyed in the direction of the arrow 137 to have the leading edge portion enter the entry nip between creasing rolls 49, 50, which as the bag top portions move between rolls 49, 50, creases the bag top along a crease line (also referred to as a fold line) 129. As may be noted from FIGURE 11, the crease line is at a lower elevation than the top edge of side wall 126. Due to the shape of the creasing roll flange 49a and a groove 590, the portion of the bag top above crease line 129 is bent to incline upwardly and transversely toward the left. As the creased portion of the bag top leaves the exit nip of the creasing rollers, it is longitudinally moved to a position to abut against forward portion 88 which in part overlays creasing roller 48 and is inclined from above creasing roller 48 to extend upwardly and transversely to the left above belt inner runs 52a, 55a to progressively fold the creased portion toward a general horizontal condition as the bag is further advanced in the direction of the arrow 137. Slight additional movement of the leading edge portion of the bag beyond the creasing roller exit nip moves the leading edge portion into the throat formed by folder blade portion 864; and shoe portion 108a. The shoe has a horizontal top edge at substantially the same elevation as that of the crease line 129 formed by the creasing rollers; and accordingly, the folding shoe folds the bag top portion about a general axis formed by the shoe top edge. That is as the bag top passes beneath central portion 87, substantially the portion of the bag top shown above crease line 129 in FIGURE 11 is folded to a generally horizontal condition as shown in FIG- DRE 6.

Still further movement of the bag brings the bag folded edge portion into underlying relationship with the central portion 87 and into overhanging relationship to the nozzle 104. As the folded portion of the bag top is moved over nozzle 104, hot air is discharged through apertures 1.67 to impinge upon the folded portion and the adhesive to activate the adhesive, and to retain the horizontally folded portion adjacent central portion 87. The adhesive is suificiently activated at the time the bag longitudinally advances rearwardly of the nozzle, and as leading edge portion of the bag is advanced to the rearward end portion of shoe 168, rear plate portion begins to further fold the bag top about crease line 129 such that as the bag top leaves the rear end of the folder blade, the adhesive strips 131, 132 and 133 have been pressed into engagement with the side wall 126 at a location below crease line 129. Shortly after the leading edge portion of the bag leaves the trailing edge 90a of the folder blade, the leading edge portion enters the entry nip between belts 114, 115 to pass between the compression rolls. The compression rolls hold inner runs of belts 114, 115 in stridiciently tight relationship that the dependingly folded portion of the bag top having the adhesive strips thereon is firmly pressed against side wall 126 at a location below crease line 129 to form a tightly sealed bag top closure. By the time the bag top leaves the exit nip between belts 114, 115 the adhesive has set suffieiently to retain the bag top in a folded, sealed condition.

To be mentioned is that during the time the machine is operating, hot air is continuously applied through tube and discharged through nozzle apertures 1117 to impinge against the adjacent surface of blade portion 87 such that portion 87 is heated between each bag passing therebeneath. The heat retained by plate 87 assists in activating the hot melt adhesive of the oncoming bag. Also to be mentioned is that the particular pattern of hot air discharged from nozzle 1G4 coincides with the pattern of hot melt adhesive on the bag top.

Although the apparatus 10 has been described with reference to forming a folded, sealed bag top closure on a gusseted type bag, it can be used to form such a closure on a non gusseted bag having a first side wall 126 and a second side wall with contiguous bottom and side edges joined to one another and the top edge of the first side wall below the top edge of the second side wall. With an upright non gusseted bag, the adhesive strips would extend across the portion of the second side wall that extends above the first side wall.

Also, the apparatus 10 likewise can be used to form a bottom closure on an empty gusseted or non gusseted bag in a manner similar to that previously described, i.e. with the open bottom stepped end being above the inner runs 52a, 55a. If a closure is to be formed on an empty stepped end bag, a conveyor assembly need not be used since belts 52, 55 supportingly convey an empty bag through apparatus 10.

Many widely apparently different embodiments of the invention may be made Without departing from the spirit and scope thereof, and it is to be understood that we do not limit ourselves to the specific embodiments herein.

What we claim is:

1. In a bag top sealing machine for a stepped end bag having hot melt adhesive on its upper end portion, a longitudinally extending frame, means mounted on the frame for supportingly holding the bag upper end portion in an upright flat folded condition below said adhesive and conveying said upper end portion in a longitudinally rearward direction, longitudinally extending hot air nozzle means mounted on the frame adjacent the conveyor means for discharging hot air under pressure in an upward direction, said nozzle means including a nozzle member having an upwardly opening discharge opening, means mounted on the frame for successively folding said stepped end portion to extend transversely over said nozzle means to have hot air discharged against said adhesive to activate the adhesive as the bag is conveyed and then further fold said bag end portion to bring the activated adhesive into abutting engagement with an adjacent portion of the bag below the stepped end portion to form a sealed bag closure, said folding means including a folder blade portion extending over said nozzle member and forwardly thereof and a longitudinally elongated backing plate joined to the folder blade portion, said nozzle means including a longitudinally elongated shoe underlying said folder blade portion and extending adjacent said backing plate, said shoe having a backing surface adjacent and shaped from the backing plate and a top folding edge, and means for driving the conveyor means to convey the 'bag in a longitudinally rearward direction.

2. In apparatus for forming a bag closure on a bag having opposite side wall portions in a flattened condition, one side wall portion having a free horizontal edge substantially spaced from the corresponding free edge of the other side wall portion, one of the side wall portions having a strip of hot melt adhesive intermediate said free edges, a longitudinally extending frame, conveyor means mounted on the frame for conveying the side wall portions in a rearward direction and supportingly retaining said side wall portions in a flattened con dition at positions adjacent and spaced from said edges, a hot air nozzle member mounted on the frame adjacent the conveyor means for discharging hot air under pressure, said nozzle member having a discharge opening for discharging hot air in a direction outwardly of said conveyor means, folder blade means mounted on the frame for successively folding said side wall portions to in part extend transversely across said nozzle member to have hot air discharged against said adhesive strip to activate the adhesive as the bag is conveyed and then further fold said side wall portions to bring the activated adhesive into abutting engagement with the side wall portion other than the one which has the adhesive strip thereon, shoe means on the frame extending transversely intermediate the nozzle member and the folder blade means and spaced from the folder blade means for cooperating with the folder blade means to fold the side wall portions to in part extend over the discharge opening, said shoe means having a backing surface adjacent the folder blade means for abutting against the side wall portions opposite the folder blade means and a folding edge intermediate the folder blade means and the conveyor means.

3. In a bag top sealing machine for a stepped end bag having hot melt adhesive on its upper end portion, a longitudinally extending frame, means mounted on the frame for supportingly holding the bag upper end portion in an upright fiat folded condition below said adhesive and conveying said upper end portion in a longitudinally rearward direction, longitudinally extending hot air nozzle means mounted on the frame adjacent the conveyor means for discharging hot air under pressure in an upward direction, means mounted on the frame for successively folding said stepped end portion to extend transversely over said nozzle means to have hot air discharged against said adhesive to activate the adhesive as the bag is conveyed and then further fold said bag end portion to bring the activated adhesive into abutting engagement with an adjacent portion of the bag below the stepped end portion to form a sealed bag closure, means for driving the conveyor means to convey the bag in a longitudinally rearward direction, said conveyor means including a pair of conveyor belts each including an inner run having a central portion and means for mounting said belts on the frame in drivable relation to the conveyor drive means with the inner runs closely adjacent one another and extending. beneath the folding and nozzle means, said frame including a top horizontal plate extending in overhanging relationship to the inner runs and the folding means, and belt guide means mounted on the frame for resiliently holding the central inner run portions closely adjacent one another, said belt guide means including a plurality of longitudinally spaced bars and spring steel plates dependingly secured to said top plate with a bar intermediate each plate and a belt inner run, a belt guide plate mounted on the lower end of each of said spring steel plates to abut against one of the inner runs to hold it adjacent the other inner run, and means mounted by each bar for resiliently urging each spring steel plate to a position to hold the guide plate in position to retain said one inner run closely adjacent the other inner run.

4. In a bag top sealing machine for a stepped end bag having hot melt adhesive on its upper end portion, a longitudinally extending frame, means mounted on the frame for supportingly holding the bag upper end portion in an upright fiat folded condition below said adhesive and conveying said upper end portion in a longitudinally rearward direction, lonigtudinally extending hot air nozzle means mounted on the frame adjacent the conveyor means for discharging hot air under pressure in an upward direction, means mounted on the frame for successively folding said stepped end portion to extend transversely over said nozzle means to have hot air discharged against said adhesive to activate the adhesive as the bag is conveyed and then further fold said bag end portion to bring the activated adhesive into abutting engagement with an adjacent portion of the bag below the stepped end portion to form a sealed bag closure, said folding means comprising a folder blade having a longitudinally elongated backing plate, a first longitudinal forward portion joined to the backing plate and curved to fold said stepped end portion from a generally vertical condition to a genera ly horizontally extending condition as the bag is conveyed, a second lonigtudinally central, generally horizontal portion joined to said backing plate and extending over said nozzle means, and a third portion joined to said backing plate and to said central portion, said third portion being of a shape to progressively curve in a longitudinally rearward direction from a general horizontal condition to a condition extending generally parallel to said backing plate and spaced therefrom approximately the thickness of the bag closure to fold the activated adhesive portion into contact with said adjacent bag portion, said nozzle means including a lonigtudinally elongated nozzle member having a plenum chamber and an upwardly directed discharge opening, and a longitudinally elongated shoe mounted on the nozzle member adjacent the backing plate, to underlay said second portion and at least a substantial part of the rearward part of said first portion, said shoe having a generally vertical surface adjacent the backing plate and a horizontal top folding edge, and means for driving the conveyor means to convey the bag in a longitudinally rearward direction.

5. The apparatus of claim 4 further characterized in that there is provided creasing roller means on the frame generally forwardly of the folder blade to crease the bag as it is conveyed at about the same elevation as said horizontal edge and to initiate the folding of the stepped end portion in the same direction as it is folded by the folder blade.

6. In a bag top sealing machine for a stepped end bag having hot melt adhesive on its upper end portion, a longitudinally extending frame, means mounted on the frame for supportingly holding the bag upper end portion in an upright flat folded condition below said adhesive and conveying said upper end portion in a longitudinally rearward direction, longitudinally extending hot air nozzle means mounted on the frame adjacent the conveyor means for discharging hot air under pressure in an upward direction, means mounted on the frame for successively folding said stepped end portion to extend transversely over said nozzle means to have hot air discharged against said adhesive to activate the adhesive as the bag is conveyed and then further fold said bag end portion to bring the activated adhesive into abutting engagement with an adjacent portion of the bag below the stepped end portion to form a sealed bag closure, and means for driving the conveyor means to convey the bag in a longitudinally rearward direction, said conveyor means including a pair of conveyor belts each having an inner run,

each inner run having a central portion, means for :mounting said belts on the frame in drivable relation to the conveyor drive means with the inner runs closely adjacent one another and extending beneath the folding and nozzle means, belt guide means mounted on the frame for resiliently holding the central inner run portions closely adjacent one another, said belt mounting means including idler pulley means mounted on the frame forwardly of said folding means, and means mounted by the idler pulley means and drivably connected thereto for creasing the stepped portion along a crease line at about the same elevation as the line of folding by the folding means, said frame includes a top horizontal plate extending in overhanging relationship to the inner runs and the folding means, and that the belt guide means includes a plurality of longitudinally spaced bars and spring steel plates dependingly secured to said top plate with a bar intermediate each plate and a belt inner run, a belt guide plate mounted on the lower end of each of spring steel plates to abut against one of the inner runs to hold it adjacent the other inner run, and means mounted by each bar for resiliently urging each spring steel plate to a position to hold the guide plate in position to retain said one inner run closely adjacent the other inner run.

7. Apparatus for forming a bag closure on a bag having opposite side Wall portions in a vertical condition, one side wall portion having a free horizontal edge substantially below a corresponding free edge of the other side wall portion and a horizontal strip of hot melt adhesive on the other side wall portion inner surface at an elevation intermediate said free edges, said apparatus comprising a longitudinally extending frame, two conveyor belts each having inner runs, means for mounting the conveyor belts on the frame and retaining the inner runs adjacent one another to hold said side wall portion adjacent one another and supportingly convey said bag in a longitudinally rearward direction, the last mentioned means including :means for driving said conveyor belts to move the conveyor belt inner runs in the same direction, the above mentioned inner runs in supportingly conveying a bag engaging said side walls at an elevation substantially below the one side wall horizontal edge, means mounted on the frame in driven relationship to said conveyor belts for creasing the side wall portions along a crease line at an elevation between said conveyor belts and the one side wall horizontal edge as the bag is supportingly conveyed, nozzle means mounted on the frame longitudinally rearwardly of the creasing means for discharging hot air under pressure in a generally upward direction, said nozzle means including a horizontally elongated hot air discharge member closely adjacent and above one of said inner runs, a longitudinally elongated folded blade having a central portion mounted on the frame to have said central portion transversely extend over said discharge member, said folder blade having means extending forward of said central portion and adjacent to said creasing means for folding said side walls about said crease line in a direction that the adhesive strip is transversely moved to a position to have hot air directly contact it as the bag is supportingly conveyed, and means extending rearwardly of said central portion for further folding said side wall portions about the crease line to a position that the adhesive strip abuts against said one side wall as the bag is supportingly conveyed, and means mounted on the frame longitudinally rearwardly of the last mentioned means for holding the further folded side wall portions in compression as the bag is supportingly conveyed by said inner runs, said nozzle means including a shoe mounted on the nozzle member to abut against said one side wall between the crease line and the conveyor belts for holding said one side wall portion closely adjacent the corresponding part of the other side wall portion as the bag is conveyed beneath said central portion, and said compression means including a pair of compression belts having longitudinally extending inner runs and means mounted on the frame for mounting the compression belts to have their inner runs above and closely adjacent the conveyor belt inner runs, the compression belt mounting means including means drivenly connected to the conveyor belt drive means for driving said compression belt inner runs in the same direction.

References Iited UNITED STATES PATENTS 1,909,319 5/1933 Taylor 53371 2,576,472 11/1951 Mess-mer et al. 53371 3,248,843 5/1966 Winters et a1 53-373 FOREIGN PATENTS 1,301,269 7/1962 France. 1,136,262 9/1962 Germany.

TRAVIS S. MCGEHEE, Primary Examiner.

R. L. SPRUILL, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIUN Patent. No. 3,381,448 May 7, 1968 Richard H. Ayres et a1.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 9 line 7, "shaped" should read spaced CclomN l0 lines 13 29 and 39 'klonigtudinally each occurrence line 5 "folded should read longitudinally Column 12 should read folder Signed and sealed this 13th day of January 1970 (SEAL) Attcst:

WILLIAM E. SCHUYLER,TR

Edward M. Fletcher, Jr.

Commissioner of Patelit Attesting ficcr 

